Hi Guys First post here. I have an organization that has this rule in place for additional work once you address the original incident:
 "If requested by the same client to do further work than initially requested in the initial ticket and it can be done in that single visit, a new ticket should not be created. The existing ticket should be updated to reflect the additional work undertaken."
I don't believe this is correct as I think a new ticket would need to be created for the additional incident/request. Can someone let me know if I am correct in following ITIL best practices.

If there is an Incident, all of the work that is directly related to the Incident - to investigate, diagnose, communicate and resolve - are linked to that incident.

Any other activities that supports the Incident should be in that ticket

The same standards would apply to Requests.

That said, If you have a request to X and the customer says do X, Y, Z, banana, etc and you do the work, you must have a way to track that - regardless of whether the customer is charged, all of that work / tasks / actions can be assigned to that ticket.

If the org is smart or charges for the work you did beyond the required, then, when the request gets reviewed, the additional tasks are there.

Please note ITIL is NOT a standard or a requirements document. It is a framework. ITIL is adopt the framework and adapt to the particular org

ITIL says all incidents and requests should be recorded and managed - how you do that is up to you